New technologies such as autonomous vehicles, virtual/augmented reality in mobile environment, mobile robots, industrial Internet of Things (IoT), mobile and distributed artificial intelligence, etc., demand much wider bandwidth for the next generation of mobile communication systems to provide mobile wireless connectivity that are significantly faster and more reliable than what's available in prior art. The 3rd Generation Partnership Project (3GPP) has defined the 5G New Radio (NR), a candidate technology for potential inclusion in the IMT-2020 radio interface recommendation(s) by ITU-R, that uses up to 100 MHz bandwidth for sub 6 GHz frequency bands and 400 MHz bandwidth for millimeter wave (mmWave) frequency bands with scalable subcarrier spacing for a single carrier for the next generation or the 5th generation (5G) wireless communication systems, e.g., at 28 GHz carrier central frequency with 3168 usable subcarriers under 120 KHz subcarrier spacing. Carrier aggregation in NR will require radio frequency (RF) transceivers with even wider bandwidth, e.g., over 1 GHz, to handle even wider bandwidth signals. With the much wider bandwidth than that in the 4G Long Term Evolution (LTE), the wideband communication systems can achieve higher peak throughput and spectral efficiency, lower latency, and better user experience. Moreover, the wide bandwidth enables more efficient use of resources than the existing carrier aggregation (CA) mechanism in 4G-LTE.
One of the major challenges of wideband communication systems is the difficulty for hardware to achieve precise and robust performance in such a wide bandwidth, e.g., the flatness of the response of the RF path. Another challenge is the high cost and high power consumption of analog-to-digital conversion (ADC) and digital-to-analog conversion (DAC) in a RF transceiver. For example, for systems with wider than 100 MHz bandwidth, sampling speed faster than 1G sample per second and bit resolution with more than 10 bits are desired. The possibility of using low bit resolution, e.g., one-bit ADC, has been studied recently to cut down system complexity and power consumption. However, even with very sophisticated algorithms, one-bit ADCs fundamentally has poor performance at medium and high SNRs. To address this issue, this patent presents invention that implement wideband transceivers using multiple narrower-bandwidth transceivers working in parallel so that the power consumption and transceiver complexity increases linearly instead of exponentially as the wireless signal bandwidth grows.